lengthfilter.cs

Lucene.Net 版本源码 测试通过

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System;

namespace Lucene.Net.Analysis
{
	
    /// <summary> Removes words that are too long and too short from the stream.
    /// 
    /// </summary>
    /// <author>  David Spencer
    /// </author>
    /// <version>  $Id: LengthFilter.java 347992 2005-11-21 21:41:43Z dnaber $
    /// </version>
    public sealed class LengthFilter : TokenFilter
    {
		
        internal int min;
        internal int max;
		
        /// <summary> Build a filter that removes words that are too long or too
        /// short from the text.
        /// </summary>
        public LengthFilter(TokenStream in_Renamed, int min, int max) : base(in_Renamed)
        {
            this.min = min;
            this.max = max;
        }
		
        /// <summary> Returns the next input Token whose termText() is the right len</summary>
        public override Token Next()
        {
            // return the first non-stop word found
            for (Token token = input.Next(); token != null; token = input.Next())
            {
                int len = token.TermText().Length;
                if (len >= min && len <= max)
                {
                    return token;
                }
                // note: else we ignore it but should we index each part of it?
            }
            // reached EOS -- return null
            return null;
        }
    }
}